CVE-2020-8290

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-12-27 · updated 2026-06-17
Weakness: CWE-269

Description

Backblaze for Windows and Backblaze for macOS before 7.0.0.439 suffer from improper privilege management in `bztransmit` helper due to lack of permission handling and validation before creation of client update directories allowing for local escalation of privilege via rogue client update binary.

Affected products

Backblaze: before 7.0.0.439 — fixed in 7.0.0.439

How to fix

Upgrade to a fixed version: Backblaze 7.0.0.439. Check the vendor advisory for mitigations.

References

https://github.com/geffner/CVE-2020-8290/blob/master/README.md
https://hackerone.com/reports/818857
https://youtu.be/OpC6neWd2aM
https://github.com/geffner/CVE-2020-8290/blob/master/README.md
https://hackerone.com/reports/818857
https://youtu.be/OpC6neWd2aM

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